How to enable telnet on the router or create an ARP entry?

Question

telnet

I set up WoL via the Internet. When the PC is turned on, the packets arrive, and after turning off the PC, after a couple of minutes it turns on due to Wol. But if you leave it off for a longer time, the MAC address of the PC is removed from the ARP table and the packets do not reach. As I understand it, you need to either make an ARP entry from the PC MAC permanent, or make an entry from IP to the broadcast MAC. How can I do that? I tried to connect via telnet, writes "Connection failed".
Router NTU-RG-1402G-W from Rostelecom. His instructions , where telnet support is declared. There is no ARP setting on the web, only browsing.
Screenshot of WoL packets
NAT router settings
Management sub-items